Aim: Determine the feasibility of ¹⁸F-florbetaben positron emission tomography (PET) in diagnosing cardiac amyloidosis. Methods: ¹⁸F-florbetaben PET was performed in 14 subjects: 5 light chain (AL) amyloid, 5 transthyretin (ATTR) amyloid, and 4 control subjects with hypertensive heart disease. Qualitative and quantitative assessments of ¹⁸F-florbetaben activity were performed using mean standardized uptake value (SUV) of the left ventricular (LV) myocardium and blood pool, and calculation of target-to-background SUV ratio. Percentage myocardial ¹⁸F-forbetaben retention was also calculated as the percentage mean myocardial SUV change between 0–5mins and 15–20mins after radiotracer injection. Global LV longitudinal and right ventricular (RV) free wall longitudinal strain were calculated using 2D speckle tracking echocardiography. Results: Target-to-background SUV ratio and percentage myocardial ¹⁸F-forbetaben retention were higher in amyloid patients compared to hypertensive control subjects. A cut-off value of 40% was able to differentiate between cardiac amyloid patients and hypertensive control subjects. Percentage myocardial ¹⁸F-forbetaben retention was an independent determinant of both global LV longitudinal and RV free wall longitudinal strain via an inverse curve relationship. Conclusion: ¹⁸F-florbetaben PET imaging can accurately identify and differentiate between cardiac amyloidosis and hypertensive heart disease. Percentage myocardial ¹⁸F-florbetaben retention was an independent determinant of myocardial dysfunction in cardiac amyloidosis.

Background: Current understanding of metabolic heart disease consists of a myriad of different pathophysiological mechanisms. Epicardial adipose tissue (EAT) is increasingly recognized as metabolically active and associated with adverse cardiovascular outcomes. The present study aimed to investigate the effect of increased EAT volume index on left ventricular (LV) myocardial fat content and burden of interstitial myocardial fibrosis and their subsequent effects on LV myocardial contractile function. Methods and Results: A total of 40 volunteers (mean age, 35±10 years; 26 males) of varying body mass index (25.0±4.1 kg/m ² ; range, 19.3–36.3 kg/m ² ) and without diabetes mellitus or hypertension were prospectively recruited. EAT volume index, LV myocardial fat content, and extracellular volume were quantified by magnetic resonance imaging. LV myocardial contractile function was quantified by speckle tracking echocardiography global longitudinal strain on the same day as magnetic resonance imaging examination. Mean total EAT volume index, LV myocardial fat content, and extracellular volume were 30.0±19.6 cm ³ /m ² , 5.06%±1.18%, and 27.5%±0.5%, respectively. On multivariable analyses, increased EAT volume index and insulin resistance were independently associated with both increased LV myocardial fat content content and higher burden of interstitial myocardial fibrosis. Furthermore, increased EAT volume index was independently associated with LV global longitudinal strain. Conclusions: Increased EAT volume index and insulin resistance were independently associated with increased myocardial fat accumulation and interstitial myocardial fibrosis. Increased EAT volume index was associated with detrimental effects on myocardial contractile function as evidenced by a reduction in LV global longitudinal strain.